On This Day . . .

Send in the Clones

January 30, 1982: Elk Cloner Released “Into the Wild”

Elk Cloner, one of the first known microcomputer viruses, is released “in the wild,” i.e., outside the computer system or lab in which it was written. It attached itself to Apple DOS 3.3 operating system and spread by floppy disk.

15-year-old high school student Rich Skrenta developed the Elk Cloner virus. Skrenta was a high school student at Mt. Lebanon High School, when he wrote the Elk Cloner virus that infected Apple II machines. It is widely believed to be the first large-scale self-spreading personal computer virus ever created.

Skrenta already had a reputation for developing computer tricks among his friends at a time before the word “virus” had even been conceived. While sharing computer games and software with his friends, Skrenta would change the floppy disks’ properties, forcing the users’ computers to shut down or display cruel messages on the screen.

His friends soon became very cautious about any disks coming from Skrenta, which is how he came to develop the self-copying aspect of the virus. During his winter school vacation, Skrenta formulated a technique to alter floppy disks without actually touching them. His newly conceived idea was later called a boot sector virus.

According to contemporary reports, the virus was rather contagious, successfully infecting the floppies of most people Skrenta knew, and upsetting many of them. Part of the “success,” of course, was that people were not at all wary of the potential problem, nor were virus scanners or cleaners available. The virus could still be removed, but it required an elaborate manual effort.

Elk Cloner spread by infecting the Apple II operating system using a technique now known as a “boot sector” virus. It was attached to a game, the game was then set to play. But on the 50th time of starting the game, the virus was released. Only on this time instead of playing the game, it would change to a blank screen that read a poem about the virus named Elk Cloner. If a computer booted from an infected floppy disk, a copy of the virus was placed in the computer’s memory. When an uninfected disk was inserted into the computer, Elk Cloner would be copied to the disk, allowing it to spread from disk to disk.